Method of physically enlarging a photographic color transparency



Nov. 20, 1951 w. J. NAGEL 2,575,970 METHOD OF PHYSICALLY ENLARGING A PHOTOGRAPHIC COLOR TRANSPARENCY Filed Feb. 19, 1947 A 5 YEBLOW |MAGE LAYER FERROTYPE TIN I MAGENTA IMAGE LAYER BASE CYANIDE IMAGE LAYER CYANIDE IMAGE LAYER BAsE APPLICATION OF TEMPofi MAGENTA IMAGE LAYER PAPER SUPPORT YELLOW IMAGE LAYER TEMPORARY PAPER suPPoFrr NOTE: suPPoRT CONTAINS MIXTURE 0F 5%NA2CO3 & 59a NAFL IMMERSION IN BASE SOLVENT BATH TRANSPARENCY TEMPORARY PAPER SUPPORT BASE SOLVENT BATH IMAGE CYANIDE IMAGE LAYER I, MAGENTA IMAGE LAYER YELLOW IMAGE LAYER WITH BASE ITEMPoRARY PAPER SUPPORT wrm NA SALT? REMovEo IMMERSION IN E I ING BATH l I BATH OF NA SALTS TEMPORARY SUPPORT TRANSPARENCY FREE FROM SUPPO AND INCREASING IN SIZE RT YELLOW IMAGE LAYER REMOVAL OF TEMPORARY MAGENTA IMAGE LAYER SUPPORT AND MOUNTING CYANIDE IMAGE LAYER F'NAL SUPPORT L FINAL PAPER SUPPORT INVENTOR. WILL/AM J NAGEL A TTOPNEI JT Patented Nov. 20, 1951 METHOD OF PHYSICALLY ENLARGING A PHOTOGRAPHIO COLOR TRANSPARENCY William J. Nagel, Bethesda, Md.

Application February 19, 1947, Serial No. 729,670

8 Claims.

The invention relates to an improved method or procedure for enlarging the superimposed multi-color layers of a photographic color film transparency and of converting such layers, into a photographic color print, and has for its objects to provide an improved and simplified procedure for such purpose as will be pointed out hereinafter.

An important object of the invention is to provide a method of the character described wherein the superimposed multi-color portion of a film transparency may be readily increased in size or enlarged to a desired degree with a facility and convenience not heretofore known or practiced by present methods.

A further object of the invention is to provide an improved and novel procedure of the character described wherein the time element for carrying out the method is materially reduced or lessened, and the disadvantages attendant upon similar procedures as heretofore known and practiced, are greatly minimized, if not entirely eliminated.

Numerous other objects and advantages of the invention will be apparent as it is better understood from the following description which discloses a preferred embodiment thereof.

Prior to the present invention the method of increasing the size of the described portions of color film transparencies as well as mounting the same on paper, was a complicated and difficult procedure.

The color film transparency involved herein may be briefly described as consisting of a series of superimposed mono-pack multi-colored emulsion layers mounted on a suitable base such as cellulose acetate or cellulose nitrate, the opposite side of the base having high temperature dissolving exterior anti-curl gelatine coating thereon. The former practice is substantially as follows:

Said multi-color plural layer film transparency is first thoroughly soaked in water together with a piece of gelatine emulsion coated photographic paper which has been previously placed in a suitable hyposulphite solution, known as hypo, for the purpose of removing the silver halide therefrom. The film and gelatine coated paper are united in emulsion to emulsion relation in the solution and then placed as a unit on a ferrotype tin to temporarily adhere the paper to the tin. The paper is of greater area than the film which results in the gelatine surface of the paper surrounding the film, being adhered to the ferrotype tin. Excess moisture then ,is removed with a flat squeegee. After the union has dried and released itself by drying from the tin, it is mounted with rubber cement on a piece or sheet of Masonite board, which is rigid and waterproof, with the back of the paper adhering to the smooth surface of Masonite. The peripherally exposed gelatine coated paper surface or area between the Masonite board and the film transparency is coated with rubber cement to prevent this exposed area from being attacked or deleteriously affected by a later treating solution. Thereafter at least one hour is required for the rubber cement to dry. When the rubber cement is dry, the paper mounted transparency and the Masonite backing are placed in a 5% ammonia solution for about ten minutes. The ammonia softens the outer exposed anti-curl gelatine coating sufficiently to enable the same to be removed by the aid of a sharp knife or razor blade. After all the gelatine has been removed, the said paper mounted multi-layer color transparency is placed in ethylene glycol mono methyl ether acetate (methyl cello-solve acetate) for a period of about thirty minutes, or until all the now outer exposed cellulose film base is dissolved or sufficiently softened by the ethylene glycol mono methyl ether acetate to permit the base to be removed from the color layers as by means of a blotter squeegee. This is a very trying operation requiring a long period of time and is very messy. After the base is removed the now outer exposed color layers with the paper support and Masonite backing sheet are placed in a bath or solution of sodium salts, for about one hour. After this period of time the work is removed from the bath and the exposed color layers may be removed from the intermediate paper mounting sheet having the Masonite backing sheet thereon. Considerable difficulty has been experienced in freeing the gelatine layers from the paper sheet and force must be applied for this purpose; hence there is a strong probability and the extreme disadvantage of thus tearing the layers with the resultant necessity of repairing the lines of fracture to conceal the damage. This is a frequent occurrence which often results in an imperfect or faulty final print. The released unitary color layers alone expand when returned to or immersed in this solution for about five minutes after their described release from the paper mounting and Masonite sheet. The thus enlarged color gelatine layers are then mounted on the described hypo treated photographic paper. Blotter squeegees are usually employed to remove the water from the print and this operation requires skill, care and considerable time.

3. for the reason that the blotters have a tendency to "grab and tear the layers with the above mentioned disadvantages. After all the water is removed so that no air bells or pockets are present, the paper mounted color layers are al-- lowed to dry. This completes the difficult and tedious operation.

In contrast with the foregoing and among other improvements which will become apparent hereinafter, I have discovered that it is possible to entirely eliminate the use of the flVlasonite board support and the rubber cement coating on the exposed gelatine surface of the paper 11301111111- ing in turn supported by the Masonite board backing.

As a result of long study and experimentation I have discovered a radically different and improved simplified method for the described enlarging purposes to obviate the disadvantages, attendant upon the former practice as well as materially reducing the time required for the operation.

My improved procedure contemplates the following muchmore simplified steps and operations which are schematically illustrated in the accompanying drawing wherein sketches A to F inclusive successively illustrate said steps in progressive order;

These progressive steps illustrated sketches may be briefly described as follows:

(A) Original transparency with its anti-curl back coating removed.

(B) Transparency without back coating sand wiched between ferrotype tin and temporary support which contains the sodium salts; Base of transparency in contact with ferrotype tin.

(C) The unit of the temporary support and transparencyafter it has released itself from the ferrotype tin is placed into a base solvent bath in order to soften base, so that it may be re':

moved.

(D) Transparency'without base mounted on temporary support.

(E) Bath of sodium salts (5% sodium carbonate and 5% sodium fluoride) where gelatine. on temporary support dissolves and liberates the sodium salts which enlarge the original transparency. The bath temperature is 126 degrees F.

(F) Mounted enlarged transparency on final paper support.

I first soak the color film or transparency of the character above described in a 5% ammonia solution for about ten minutes; then remove the anti-curl gelatine backing or base (sketch A) from the film, for example by scraping with a. knife or razor blade, as a result of softening the backing by this soaking treatment. The color layer film is then mounted on a paper support of larger size (sketch B) having, an emulsion coating of low temperature dissolving gelatine,

. which contains a sodium salt or preferablya mixture of sodium fluoride and sodium carbonate. ,For example about 5% sodium fluoride and so dium carbonate by weight I have found sati'" is allowed to dry.

When the mounted color transparency and its. united paper support are dry, the same are removed as a unit from the ferrotype tin' and placed in a bath of ethylene glycol mono methyl acetate for about ten minutes (sketch C) after which the; y

in said excess liquid bath is removed as by a squeegee. The mounted color transparency is next placed -lace up on a piece of glass for about an hour to permit the cellulose base component of the trans- .color'layers by means of inserting a: knife blade or the like at one corner, after which the cellulose' base may be grasped by the fingers and pulled or rolled from the color layers and discarded, thereby exposing these color layers as an'out'er surface on the gelatine coated paper mounting sheet (sketch D).

There are many solvents which will work with equal facility, some of which are ethyl acetoacetate, propyl acctoacetate, butyl 'acetoacetate, ethyl acetate, di-ethyl chloride, and methyl ethyl maining portions of the base therefrom.

Thesenow exposed color layers are then allowed to dry. When dry they are placed in cold water, removed and examined for any ridges thereon which would indicate that the cellulose base is not completelyremoved. The color layers are again allowed. to dry prior to againbein placed or immersed in the solvent, so as to comwhich time the gelatine coating on the paper is completely dissolved, leaving the color layers free and separated from the paper mounting. The sodium fluoride and sodium carbonate which were formerly inseparably andhomogeneously incorporated in the low temperature dissolving gelatine emulsion in the paper backing, are now liberated in this Warm water bath. The sodium salts react chemically with the superposed color layers in such manner that the layers are initially and materially enlarged in the bath in respect to their linear dimensions, within a comparatively short period of time. I

These enlarged color layers alone are then preferably placed as a unit in another bath of warmer water at about F. for about three minutes, where an additional and substantial swelling or enlargement of the layers occurs. An 8 x 16" original mono-pack will'thusincrease in overall size approximately to 11" x 14" 'in a total time of approximately eight minutes,

as compared to approximately one hour according to present methods.

The enlarged superposed unitary multi-color layers, treated and increased in dimensional size to the desired degree or extent, in accordance with the foregoing described procedure, are now in condition to be transferred as a unit onto a permanent support or mounting such as gelatine coated paper (sketch F). This mounting may consist of paper, glass or any desired mounting surface which has been coated with gel-atine. Preferably the surface of the mounting upon i which the gelatine coating is applied should be white.

After the thus enlarged multi-color layers are transferred and smoothedas a unit onto the final or permanent support or surface, a piece of clear celluloid may be laid over the surface of the layers, and a rubber or blotter squeegee is used to remove excess Water. Should any minute air bubbles form, these may be removed either by working them outwardly to the edge of the work with a Wet finger, or by piercing the bubbles with a fine needle.

After the multi-layer color print which has been enlarged to the desired degree in accordance with the described improved method, is free from all bubbles, it is allowed to dry. The finally completed print may be thereafter waxed if desired.

My improved method is far superior to methods now commonly employed for the reason that less attention and working time are required to remove in separate operations the anti-curl gelatine backing and the cellulose base, and the technique is much more clean.

From the foregoing it will be obvious that by my improved process I have eliminated the Masonite backing board and rubber cement protective coating on the exposed gelatinized portions of the color film mounting, and the time incident to drying thereof. Also I do not employ with the described disadvantages, the chemical compounds such as sodium fluoride and sodium carbonate directly as a diluent of the immersion bath, as in the instance of present practice. In

' contrast therewith I incorporate such sodium salt or salts as a constituent of the low temperature dissolving gelatine coating on the paper mounting. These chemical constituents are liberated in um carbonate serves to open the pores of the gelatine on the paper mounting to permit Water to enter and swell the mounting. The sodium fluoride materially aids the water to etch the gelatine to promote access of Water to the gelatine coating on the paper.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing description, and it Will be apparent that various changes may be made in the steps of the process described and their order of accomplishment without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the method hereinbefore described being merely a preferred embodiment thereof,

What is claimed is:

1. The method of enlarging the gelatinized multi-color layers of a photographic transparency having a cellulose base and an anti-curl gelatine backing, which consists in softening said backing by means of a solvent and then removing the backing from the base, mounting said transparency including the cellulose base on a temporary support having a gelatine emulsion coating thereon containing a mixture of sodium salts with the gelatinized surfaces of the transparency and support disposed in face to face relation, placing said mounted transparency in a solvent to soften the base, removing said base to leave only the multi-color layers on said support as a unitary sheet, subjecting said sheet to contact with Warm water to dissolve the gelatine thereon and liberate the sodium salts to activate and enlarge by swelling the dimensions of said multi-color layers while separating said layers from the temporary support, to thereby condition said layers for transfer as an enlarged unit onto a permanent support.

2. The method of enlarging the gelatinized multi-color layers of a photographic transparency having a cellulose base and an anti-curl gelatine backing, which consists in softening said backing by means of a solvent and then removing the backing from the base, mounting said transparency including the cellulose base on a temporary paper support having a gelatine emulsion coating thereon containing a mixture of sodium salts with the gelatinized surfaces of the transparency and support disposed in face to face relation, placing said mounted transparency in a solvent to soften the cellulose base thereof, removing said base to leave the multi-color layers only on said paper support as a unitary sheet of substantially the same size as the original transparency, subjecting said sheet to contact with warm water to dissolve the gelatine portion of the coating thereon and liberate the sodium salts to activate and enlarge by proportionate swelling the dimensions of said multi-color layers While separating said layers from the temporary paper support, and finally subjecting the layers to contact with Warmer Water to further enlarge and proportionately swell the dimensions of the layers, thereby conditioning said layers for transfer as an enlarged unit to a permanent mounting support.

3. The method of enlarging as a unit the plural layer multi-color portion of a color film transparency having a cellulose base and an anticurl gelatine backing thereon, which consists in first removing the gelatine backing from said cellulose base, mounting said base cellulose and said plural color layers on a low temperature dissolving gelatine coated temporary paper support with the gelatinized surfaces of the transparency and support disposed in face to face, relation, said gelatinous coating containing approximately 5% each of sodium fluoride and sodium carbonate incorporated therein, removing the cellulose base from said transparency while on said paper support, immersing said paper support and said color layers as an integral unit in a bath of warm water to initially separate said unitary layers from said paper support and to simultaneously liberate in the bath the sodium fluoride and sodium carbonate constituents of the gelatine coating on the paper support to cause them to chemically react with the color layers to swell and enlarge the iinear dimensions of said layers, and finally immersing the thus enlarged and separated multi-color layers alone in another bath of water of higher temperature than said first mentioned bath to further chemically activate and similarly enlarge the size of said layers and condition the same for mounting as an enlarged integral unit on a permanent support.

a. The method of enlarging the gelatinized rulti-color layers of a photographic transparency having a cellulose base and a high temperature anti-curl gelatine backing, which consists in softening said backing by means of an ammonia containing solvent and then removing the backing from the base, mounting said transparency including the cellulose base on a temporary paper support having a low temperature dissolving gelatine emulsion coating containing sodium fluoride and sodium carbonate in substantially equal proportions of 5 percent each with the gelatinized surfaces of the transpararmy and paper support disposed in face to face relation, placing said mounted transparency in a solvent to soften the base and then removing said base to leave the multi-color layers only on said paper support as a unitary sheet of substantially the same size as the original transparenoy, soaking said sheet emulsionto emulsion in a bath of Warm water to dissolve the low temperature dissolving gelatine thereon and thereby liberate the sodium salts to activate and enlarge by proportionate swelling the dimensions of said multi-color layers while physically separating from,the temporary paper support, removing said layers only as a unit from said bath and soaking the layers in another bath of warmer water to further similarly en'- large the dimensions of the layers, thereby conditioning said layers for transfer as an enlarged unit to a permanent support.

5. The method of enlarging the gelatinized multi-color layers of a photographic transparency having a cellulosebase and an anti-curl gelatine backing, which consists in softening said backing by means of an ammonia containing solvent and then removing the backing from the base, mounting said transparency including the cellulose base on a temporary paper support having a low temperature dissolving gelatine emulsion coating containing approximately sodium fluoride and approximately 5% sodium carbonate by Weight With the gelatinized surfaces of the transparency and paper support disposed in face to face relation, placing said mounted transparency in a solvent to soften the base, rolling off said base as a unitary mass to leave the multi-color layers only on said paper support as a unitary sheet of substantially the same size as the original transparency, drying and then immersing said paper supported layers in a cold Water bath to visually determine whether said base has been completely removed, im-

mersing said sheet emulsion in Warm Water to dissolve the loW temperature gelatine component thereon'and thereby liberate the said sodium salts to activate the constituents of said multi color layers to thereby enlarge by proportionate planar swelling the dimensions of the same while at the same time physically separating them from the temporary paper support, removing said layers only as a unit from said bath and im- 1 mersing the layers in warmer water to further similarly enlarge the dimensions of the layers, and finally transferring said layers as an enlarged unit to a permanent support mounting.

6. The method of enlarging as a unit the plural'layer multi-color portion of a color film transparency having a cellulose base and an anti-curl gelatine backing thereon, which consists in first removing the gelatine backing from base, mounting said cellulose base and said plural layers on a low temperature dissolving gelatine containing temporary paper support, said gelatine on the paper support having a mixture of sodium salts in substantially equal proportions of 5 percent each incorporated therein, the gelatinized surfaces of the transparency and paper support being disposed in face to face relation, removing the base from said paper supported color layers, and subjecting said layers to contact With Warm Water to separate said unitary layers from said paper support and to liberate the sodium salt constituents of 'the support to cause the same to chemically react with the color layers to enlarge by planar swelling the dimensions of said layers. Y

7. The method of enlarging as a unit the plural layer multi-color portion of a color, film transparency having a cellulose base and an anticurl gelatine backing thereon, which consists in first removing the gelatine backing from said base, mounting said cellulose base and said'plural layers on a low temperature dissolving gela tine containing temporary paper support with the gelatinized surfaces of the transparency and support disposed in face to face relation, the

supported layers in a bath of Warm water to Y physically separate as a unit said layers from the paper support and to coincidentally liberate the sodium fluoride and sodium carbonate constituents of the paper support to permit them to chemically react in the bath with the chemical constituents of the color layers to swell and enlarge the linear dimensions of said layers 8. The method of enlarging as a unit the plural layer multi-colo'r portion of a color film transparenoy having a cellulose base and an anti-curl gelatine backing thereon, which consists in first removing the gelatine backing 'from said cellulose base, mounting said cellulose base and said plural color layers on a low temperature dissolving gelatine containing temporary paper support with the gelatinized surfaces of the transparency and support disposed in face to face relation, said gelatine containing paper support having a mixture of sodium salts incor porated therein in substantiallyequal proportions of 5 percent each, rolling the base of the unit from said paper supported layers, subjecting said color layers to contact with Warm Water to initially separate said unitary color layers from said paper support and to liberate the sodium salt constituent of the support to cause the salts to chemically react with'the color layers to proportionately swell and enlarge the dimensions of said layers, and finally subjecting the thus enlarged and separated multi-color lay: ers alone to further contact with warm water 'at a higher temperature than said first mentioned water to further chemically activate and similarly enlarge the size of said layers.

WILLIAM J. NAGEL.

REFERENCES CITED The following references are of record in the Great'Britain July 4, 1940 

1. THE METHOD OF ENLARGING THE GELATINIZED MULTI-COLOR LAYERS OF A PHOTOGRAPHIC TRANSPARENCY HAVING A CELLULOSE BASE AND AN ANTI-CURL GELATINE BACKING, WHICH CONSISTS IN SOFTENING SAID BACKING BY MEANS OF A SOLVENT AND THEN REMOVING THE BACKING FROM THE BASE, MOUNTING SAID TRANSPARENCY INCLUDING THE CELLULOSE BASE ON A TEMPORARY SUPPORT HAVING A GELATINE EMULSION COATING THEREON CONTAINING A MISTURE OF SODIUM SALTS WITH THE GELATINIZED SURFACES OF THE TRANSPARENCY AND SUPPORT DISPOSED IN FACE TO FACE RELATION, PLACING SAID MOUNTED TRANSPARENCY IN A SOLVENT TO SOFTEN THE BASE, REMOVING SAID BASE TO LEAVE ONLY THE MULTI-COLOR LAYERS ON SAID SUPPORT AS A UNITARY SHEET, SUBJECTING SAID SHEET TO CONTACT WITH WARM WATER TO DISSOLVE THE GELATINE THEREON AND LIBERATE THE SODIUM SALTS TO ACTIVATE AND ENLARGE BY SWELLING THE DIMENSIONS OF SAID MULTI-COLOR LAYERSS WHILE SEPARATING SAID LAYERS FROM THE TEMPORARY SUPPORT, TO THEREBY CONDITION SAID LAYERS FOR TRANSFER AS AN ENLARGED UNIT ONTO A PERMANENT SUPPORT. 